This application claims priority to and the benefit of Korean Patent Application Nos. 10-2011-0091760, 10-2011-0112480, 10-2011-0113915, 10-2012-0002616, 10-2012-0022940, and 10-201 2-00991 44 filed in the Korean Intellectual Property Office on Sep. 9, 2011, Oct. 31, 2011, Nov. 3, 2011, Jan. 9, 2012, Mar. 6, 2012, and Sep. 7, 2012, respectively, the entire contents of which are incorporated herein by reference.
(a) Field of the Invention
The present invention generally relates a multicast service managing method and apparatus.
(b) Description of the Related Art
A multicast service is used to a group communication where users join in a conversation. In the group communication, the same downlink traffic is simultaneously transmitted to all the users in a group for performing the group communication. Therefore, the users joining the group communication use a multicast connection to transmit data of the group communication.
Even if a mobile station receiving a multicast service enters a power saving mode, the multicast service is required to be seamlessly provided. In a general communication service, the power saving mode is independently applied to each mobile station. However, in the multicast service, the power saving mode is required to be simultaneously applied to all users within a multicast group.
Embodiments of the present invention provide a multicast service managing method and apparatus for supporting a power saving mode in a multicast service.
According to an embodiment of the present invention, a method of managing a multicast service is provided by a mobile station. The method includes receiving a message including information on a multicast indication cycle from a base station, the multicast indication cycle including a multicast available interval and a multicast unavailable interval, receiving a multicast indicator in the multicast available interval of the multicast indication cycle, and receiving a multicast traffic at a transmission time indicated by the multicast indicator.
The multicast indicator may include a multicast group identifier in which the multicast traffic is transmitted and a transmission time of the multicast traffic.
A plurality of multicast groups may be divided into a plurality of subgroups, and the multicast indicator may include a multicast group indicator and a multicast traffic indicator. In this case, the multicast group indicator may include information on a subgroup in which there is a multicast traffic to be transmitted and a transmission time of the multicast traffic indicator. The multicast traffic indicator may include information on a multicast group identifier in which there is a multicast traffic to be transmitted and a transmission time of the multicast traffic.
The information on the subgroup may be represented as a bitmap. In this case, a plurality of bits of the bitmap may correspond to the plurality of subgroups, respectively. When the value of each bit of the bitmap is any one of 0 and 1, there may be a multicast traffic for at least one multicast group of a subgroup corresponding to said bit. When the value of each bit of the bitmap is the other one of 0 and 1, there may be no multicast traffic for any multicast groups of a subgroup corresponding to said bit.
Each bit of the bitmap may indicate predetermined most significant bits of the multicast group identifier. A number of predetermined most significant bits may be a number of the subgroups.
The information on the multicast group identifier may be represented as a bitmap. In this case, a plurality of bits of the bitmap may correspond to the plurality of multicast groups included in a corresponding subgroup, respectively. When the value of each bit of the bitmap is any one of 0 and 1, there may be a multicast traffic for a multicast group corresponding to said bit. When the value of each bit of the bitmap is the other one of 0 and 1, there may be no multicast traffic for a multicast group corresponding to said bit.
Each bit of the bitmap may indicate predetermined least significant bits of the multicast group identifier. A number of predetermined least significant bits may be a number of the multicast group included in the corresponding subgroup.
The information on the multicast indication cycle may include predetermined least significant bits of a frame number or a superframe number indicating a start of the multicast indication cycle.
The multicast available interval may correspond to the first frame or the first superframe of the multicast indication cycle.
According to another embodiment of the present invention, a method of managing a multicast service is provided by a base station. The method includes transmitting a message including information on a multicast indication cycle to a mobile station, the multicast indication cycle including a multicast available interval and a multicast unavailable interval, transmitting a multicast indicator in the multicast available interval of the multicast indication cycle, and transmitting a multicast traffic at a transmission time indicated by the multicast indicator.
The multicast indicator may include a multicast group identifier in which the multicast traffic is transmitted and a transmission time of the multicast traffic.
A plurality of multicast groups may be divided into a plurality of subgroups, and the multicast indicator may include a multicast group indicator and a multicast traffic indicator. In this case, the multicast group indicator may include information on a subgroup in which there is a multicast traffic to be transmitted and a transmission time of the multicast traffic indicator. The multicast traffic indicator may include information on a multicast group identifier in which there is a multicast traffic to be transmitted and a transmission time of the multicast traffic.
The information on the subgroup may be represented as a bitmap. In this case, a plurality of bits of the bitmap may correspond to the plurality of subgroups, respectively. When the value of each bit of the bitmap is any one of 0 and 1, there may be a multicast traffic for at least one multicast group of a subgroup corresponding to said bit. When the value of each bit of the bitmap is the other one of 0 and 1, there may be no multicast traffic for any multicast groups of a subgroup corresponding to said bit.
Each bit of the bitmap may indicate predetermined most significant bits of the multicast group identifier. A number of predetermined most significant bits may be a number of the subgroups.
The information on the multicast group identifier may be represented as a bitmap. In this case, a plurality of bits of the bitmap may correspond to the plurality of multicast groups included in a corresponding subgroup, respectively. When the value of each bit of the bitmap is any one of 0 and 1, there may be a multicast traffic for a multicast group corresponding to said bit. When the value of each bit of the bitmap is the other one of 0 and 1, there may be no multicast traffic for a multicast group corresponding to said bit.
Each bit of the bitmap may indicate predetermined least significant bits of the multicast group identifier. A number of predetermined least significant bits may be a number of the multicast group included in the corresponding subgroup.
The information on the multicast indication cycle may include predetermined least significant bits of a frame number or a superframe number indicating a start of the multicast indication cycle.
The multicast available interval may correspond to the first frame or the first superframe of the multicast indication cycle.
According to yet another embodiment of the present invention, an apparatus for managing a multicast service is provided. The apparatus includes a receiver and a controller. The receiver receives from a base station a message including information on a multicast indication cycle including a multicast available interval and a multicast unavailable interval, receives a multicast indicator in the multicast available interval of the multicast indication cycle, and receives a multicast traffic at a transmission time indicated by the multicast indicator. The controller identifies the multicast available interval of the multicast indication cycle, and identifies the transmission time indicated by the multicast indicator.
According to yet another embodiment of the present invention, an apparatus for managing a multicast service is provided. The apparatus includes a transmitter and a controller. The transmitter transmits to a mobile station a message including information on a multicast indication cycle including a multicast available interval and a multicast unavailable interval, transmits a multicast indicator in the multicast available interval of the multicast indication cycle, and transmits a multicast traffic at a transmission time indicated by the multicast indicator. The controller generates the multicast indicator including the transmission time.
In the following detailed description, only certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
In the specification, the term “mobile station (MS)” may designate a terminal, a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station (HR-MS), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (AT), a user equipment (UE), and so on, or may include all or some functions thereof.
Further, the term “base station” (BS) may designate an advanced base station (ABS), a high reliability base station (HR-BS), a node B, an evolved node B (eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), an MMR (mobile multihop relay)-BS, a relay station (RS) performing base station function, a relay node (RN) performing base station function, an advanced relay station (ARS) performing base station function, a high reliability relay station (HR-RS) performing the base station function, a small cell BS (femto BS, home node B (HNB), pico BS, metro BS, micro BS, and so on), and so on, or may include all or some functions thereof.
Referring to
The base station 110 uses a flow identifier (FID) for identifying a connection besides the multicast group ID. The base station 110 allocates the FID in each multicast group ID, thereby uniquely identifying the connection, i.e., a service flow within the multicast group. Since the FID is an ID for identifying a signal or traffic connection within the multicast group, a particular connection of the multicast group can be identified a combination of the multicast group ID and FID in the base station 110. That is, the base station 110 uses the multicast group ID and the FID to provide the multicast group 120 with a multicast service. The same FID (FID0 or FID) may be used in the other multicast groups 120, 130, and 140.
Referring to
Other multicast group IDs (MGID0, MGID1, MGID2, MGID3, MGID4, and MGID5) are used in different multicast groups 220, 230, and 240. A multicast resource allocated to the multicast service can be notified to the multicast group through the multicast group ID.
Referring to
In the multicast group zone, a set of base stations uses the same multicast group ID and FID or the same multicast group ID for transmitting data of a certain service flow. Accordingly, if a mobile station has already registered with a base station for a multicast service, the mobile station can be seamlessly receive the multicast service without reregistering with other base station even if the mobile station moves to the other base station within the same multicast group zone. If the mobile station moves from a base station to another base station, those base stations provide the same multicast service but belong to different multicast group zone, the mobile station can seamlessly receive the multicast service by updating a parameter associated with the multicast service.
If only one base station belongs to a multicast group zone, the single base station uses a multicast group ID for providing a multicast service, independently from other base stations.
Referring to
When the mobile station 41 registers to receive the multicast service, either the mobile station 41 or the base station 42 initiates a dynamic service addition (DSA) procedure for a multicast connection service (S420). The one node of the mobile station 41 and the base station 42 transmits a DSA-REQ message to the other node and receives a DSA-RSP message from the other node such that the multicast connection is established.
The DSA-REQ and DSA-RSP messages include a multicast parameter associated with the multicast service. The multicast parameter includes a multicast group ID of a multicast group to which a service flow is added. The multicast parameter may further include a FID associated with the multicast group ID.
Further, when a multicast group zone is supported, the multicast parameter may further include a multicast group zone ID where the service flow is valid. The mobile station 41 can add the service flow for starting a multicast service by the multicast parameter. Alternatively, the base station may periodically broadcast a multicast group zone ID through a broadcast message. If the multicast group zones are not locally overlapped with each other and are identified from each other (that is, a base station belongs to only one multicast group zone or the multicast group zone is not defined), the multicast parameter of the DSA-REQ or DSA-RSP message may not include multicast group zone ID.
The mobile station 41 and the base station 42 may not exchange a multicast service capability in the REQ-REQ/RSP exchange procedure (S410) but exchange the multicast service capability in the DSA-REQ/RSP exchange procedure (S420).
As such, after establishing the service flow, the mobile station 41 receives a downlink control channel including multicast resource allocation information from the base station 42 (S430), and receives multicast data from the base station 42 through the allocated resource (S440).
When a change of the service flow is required in the multicast service, the mobile station 41 and the base station 42 may perform a dynamic service change (DSC) procedure. That is, any one node of the mobile station 41 and the base station 42 transmits a DSC-REQ message, and the other node responds as a DSC-RSP message. In this case, the DSC-REQ message and the DSC-RSP message include a multicast parameter. The multicast parameter may include a current multicast group ID and a new multicast group ID, or current multicast group ID and FID and new multicast group ID and FID. The multicast parameter may further include a new multicast group zone ID.
When the multicast service is terminated, the mobile station 41 and the base station 42 may perform a dynamic service delete (DSD) procedure to delete the service flow. In this case, the multicast service of the multicast group may be terminated using the multicast group ID in the DSD procedure. The base station may terminate the multicast service using the multicast group zone ID in the DSD procedure. Any one node of the mobile station 41 and the base station 42 transmits a DSD-REQ message, and the other node responds as a DSD-RSP message.
As described above, according to an embodiment of the present invention, a mobile station and a base station can identify a supported multicast service through an exchange of a multicast service capability, and add, change or delete a service flow for the multicast service through a DSx (DSA, DSC, or DSD) procedure.
On the other hand, the mobile station receiving the multicast service may enter a power saving mode such as an idle mode or a sleep mode. Operations of the mobile station and the base station are described with reference to
Referring to
The multicast available interval is an interval for indicating a connection establishment/change/delete for a multicast service within a multicast indication cycle or for indicating whether to transmit data or not after the connection establishment. A multicast indicator is transmitted in the multicast available interval. When the management cycle and the service cycle are independently operated, different indicators or a single indicator may exist for the cycles. The indicator may be provided through a message, a control channel, or a MAC header. The multicast unavailable interval is an interval for the power saving. The indicator operated in the management cycle or the service cycle is not transmitted in the multicast unavailable interval.
Each of mobile stations MS1, MS2, MS3, and MS4 has a power saving cycle such a paging cycle or sleep cycle in a power saving mode. The power saving cycle has a paging listening interval and a paging unavailable interval. The paging listening interval and the paging unavailable interval may be referred to as a listening window and a sleep window, respectively. An example shown in
When providing the mobile station with the multicast indication cycle information, the base station may provide at least two among duration of the multicast indication cycle, the multicast available interval, and the multicast unavailable interval. Alternatively, the base station may provide only the duration of the multicast indication cycle. The multicast available interval may be set as the first some frame(s) or superframe(s) of the multicast indication cycle. For example, the multicast available interval may be the first frame or superframe of the multicast indication cycle. Further, the start of the multicast indication cycle may be provided as some information of a frame number or a superframe number. For example, the start of the multicast indication cycle may be indicated in unit of predetermined least significant bits (LSBs), for example 8 LSBs, of the frame number or the superframe number.
Referring to
Referring to
When the MG-IND indicates multicast traffic transmission information directly, the MG-IND includes a multicast group ID and a transmission point of the traffic as shown in a table 1 or 2. The transmission pint may an offset of a multicast traffic. The offset of the multicast traffic may be represented as a frame number offset in which the base station transmits the multicast traffic on the basis of a transmission point (e.g., time, frame, etc.), some bits (for example, 4 LSBs) of a frame or superframe number, or a time.
Referring to a table 3 or 4, when the MG-IND does not indicate the multicast traffic transmission information directly, the MG-IND includes information on a multicast group or subgroup in which there is a multicast traffic to be transmitted and a transmission point of the MT-IND. The MG-IND may indicate several MT-INDs as shown in
Referring to the table 3, the MT-IND includes information on a multicast group ID and a transmission point of the multicast traffic, in order to indicate that the multicast traffic is transmitted. The transmission point of the multicast traffic may be a frame or time offset of the multicast traffic on the basis of a point (time or frame) when the MT-IND is transmitted. The offset of the multicast traffic may be represented as a frame number offset in which the base station transmits the multicast traffic, or some bits (for example, 4 LSBs) of a frame or superframe number.
In the MG-IND, the information on the multicast group or subgroup may be represented as a bitmap. For example, the MG-IND may include a multicast group indicator bitmap (MGIND bitmap) with M bits. M corresponds to the number of subgroups, and the number of multicast groups included in each subgroup is 2ML/M. ML is a length (length of bit) of the multicast group ID. M may be varied according to the length (ML) of the multicast group ID, and may have any one of 20, 21, . . . , and 2ML−1. For example, when M is 2ML/2, M may be 64 in the multicast group ID with 12 bits, and 256 in the multicast group ID with 16 bits. A value of M may be included in the MG-IND or another message, or may be predefined. The N-th bit of the MGIND bitmap indicates a subgroup of multicast groups ((2ML×N/M) to (2ML×(N+1)/M−1)). When N is 0, the N-th bit corresponds to a most significant bit (MSB) of the MGIND bitmap. When a value of the N-th bit is 0, there is no multicast traffic for any multicast groups in the corresponding subgroup. When the value of the N-th bit is 1, there is a multicast traffic for at least on multicast group in the corresponding subgroup. The values of the bit may be defined oppositely.
In the MT-IND, the multicast group ID information may be represented as a bitmap. For example, the MT-IND may include a multicast traffic indicator bitmap (MTIND bitmap) with K bits. K corresponds to the number of multicast groups in a subgroup, and is 2ML/M. For example, when M is 2ML/2, K is equal to M. The Q-th bit of the MTIND bitmap corresponds to a multicast group ID in the subgroup. When Q is 0, the Q-th bit corresponds to the MSB of the MTIND bitmap. When a value of the Q-th bit is 0, there is no multicast traffic for the corresponding multicast group. When the value of the Q-th bit is 1, there is a multicast traffic for the corresponding multicast group. The values of bit may be defined oppositely.
The N-th bit of the MGIND bitmap indicates log(M) MSBs of the multicast group ID, and the Q-th bit of the MTIND bitmap indicates log(K) LSBs of the multicast group ID. Therefore, the multicast group ID may be identified by the MGIND bitmap and the MTIND bitmap. For example, when the multicast group ID has 16 bits, the N-th bit of the MGIND bitmap indicates log(M) MSBs, i.e., log256(=8) MSBs, and the Q-th bit of the MTIND bitmap indicates log(K) LSBs, i.e., log256(=8) LSBs. Therefore, the multicast group ID with 16 bits can be indicated.
In an example shown in
Tables 1 and 2 show examples of the MG-IND, and tables 3 and 4 show examples of the MT-IND.
As described above, according to an embodiment of the present invention, the mobile station determines whether there is the multicast traffic for the multicast group to which it belongs based on the multicast indicator that is received in the multicast available interval of the multicast indication cycle. When there is the multicast traffic, the mobile station can end the power saving mode or receive the multicast traffic at the time indicated by the multicast indicator without ending the power saving mode. Therefore, the power saving mode can be simultaneously supported for all of the mobile stations that belong to the same multicast group. Further, the multicast service managing method according to an embodiment of the present invention can be applicable to a mobile station that has not entered the power saving mode.
When a transmission of the multicast traffic that is persistent during a predetermined interval ends, the mobile station repeats the multicast available interval and the multicast unavailable interval in accordance with the multicast indication cycle. The multicast indicator may indicate a time when the transmission of the multicast traffic ends. Further, the multicast indicator may indicate a transmission time of a next multicast traffic each time the transmission of each multicast traffic ends, and may indicate a time when the transmission of the multicast traffic ends at the transmission time of a previous traffic or indicate, after the multicast traffic is transmitted, that the transmission of the multicast traffic ends.
Furthermore, the multicast indicator may indicate a management such as a connection establishment/delete/change or an update of a multicast parameter. The mobile station can end the power saving mode and perform a ranging or transmit/receive a message, or temporarily end the power saving mode and perform the ranging, in order to update the multicast parameter. The mobile station may notify the base station, by using a ranging request message, that it will perform the ranging to update the multicast parameter. The base station may transmit to the mobile station a ranging response message including the multicast parameter.
As described above, a multicast indication cycle for indicating a data transmission may be included to a multicast indication cycle before a connection establishment such that an operation method depending on the multicast indication cycle may be used.
Next, messages for transmitting a multicast indication cycle according to various embodiments of the present invention are described with reference to
Referring to
Referring to
Referring to
Referring to
The RNG-RSP message includes multicast indication cycle information. The RNG-RSP message may further include a multicast group ID and a multicast group zone ID for updating the multicast parameter.
Referring to
Alternatively, the multicast indication cycle may be transmitted through another broadcast message. The broadcast message, for example, is a system configuration descriptor (SCD) message or a downlink channel descriptor (DCD) message.
When the broadcast message such as the NBR-ADV message, the SCD message, or the DCD message includes the multicast indication cycle information, a message such as the DSA message or the DSC message may not include the multicast indication cycle information.
Next, a multicast service managing apparatus for performing a multicast service managing method according to an embodiment of the present invention will be described with reference to
Referring to
The receiver 1410 receives a message including multicast indication cycle information from a base station, receives a multicast indicator in a multicast available interval of a multicast indication cycle, and receives a multicast traffic at a transmission time indicated by the multicast indicator. The controller 1420 identifies the multicast available interval of multicast indication cycle based on the multicast indication cycle information, and identifies the transmission time indicated by the multicast indicator.
Referring to
The transmitter 1510 transmits a message including multicast indication cycle information to a mobile station. The controller 1520 generates a multicast indicator including a transmission time of a multicast traffic. The transmitter 1510 transmits the multicast indicator in a multicast available interval of a multicast indication cycle, and transmits the multicast traffic at the transmission time indicated by the multicast indicator.
At least some functions of a multicast service managing apparatus and method according to an embodiment of the present invention may be configured by hardware or software combined with the hardware. For example, a processor configured by a central processing unit (CPU), a chipset, or a microprocessor, etc. may perform a function of a controller 1420 or 1520. A physical memory may store multicast indication cycle information, a multicast indicator, a multicast traffic, and messages. Further, a transceiver may perform a receiver 1410 or a transmitter 1510.
While this invention has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
10-2011-0091760 | Sep 2011 | KR | national |
10-2011-0112480 | Oct 2011 | KR | national |
10-2011-0113915 | Nov 2011 | KR | national |
10-2012-0002616 | Jan 2012 | KR | national |
10-2012-0022940 | Mar 2012 | KR | national |
10-2012-0099144 | Sep 2012 | KR | national |